Our Collective Sleeping Delusion

Why do we choose to sleep together, and claim that we sleep better that way, when in fact we sleep worse? This seems an obvious example of signaling aided by self-deception. It looks bad to your spouse to want to sleep apart. In the recent movie Hope Springs, sleeping apart is seen as a big sign of an unhealthy relation; most of us have internalized this association. So to be able to send the right sincere signal, we deceive ourselves into thinking we sleep better.